Antitumor peptides

ABSTRACT

Novel compounds of the formulaR1R2N-CHX-CO-A-B-D-(E)s-(F)t-(G)U-KIin which R1, R2, A, B, D, E, F, G, K, X, s, t, and u have the meanings stated in the description, and the preparation thereof are described. The novel substances have an antineoplastic effect.

This application is a continuation-in-part of application Ser. No. 08/431,795, filed May 1, 1995, now abandoned, which is a continuation of application Ser. No. 07/985,696 filed Nov. 25, 1992, now abandoned, which is a continuation-in-part of application Ser. No. 07/885,788 filed May 20, 1992, now abandoned.

BACKGROUND OF THE INVENTION

It is known that peptides isolated from marine origin like Dolastatin-10 (U.S. Pat. No. 4,816,444) and Dolastatin-15 (EP-A-398558) show potent cell growth inhibitory activity (cf.: Biochem. Pharmacology 40, no. 8, 1859-64, 1990); J. Natl. Cancer Inst. 85, 483-88, 1993 and references cited therein). Based upon interesting results in experimental tumor systems in vivo, further preclinical evaluation of these natural products is currently under way in order to initiate clinical studies in cancer patients. However, the natural products have disadvantages, such as poor solubility in aqueous solvents and costly building blocks needed for synthesis. The invention described herein provides novel peptides and derivatives thereof which offer improved therapeutic potential for the treatment of neoplastic diseases as compared to Dolastatin-10 and Dolastatin-15. Furthermore, the compounds of this invention may be conveniently synthesized as described in detail below.

DETAILED DESCRIPTION OF THE INVENTION

Compounds of this invention include novel peptides of the formula I

    R.sup.1 R.sup.2 N--CHX--CO--A--B--D--(E).sub.s --(F).sub.t --(G).sub.U --KI

where

R¹ is alkoxy, preferably C₁ -C₄ ; alkyl, preferably C₁₋₇ ; cycloalkyl, preferably C₃₋₆ ; alkylsulfonyl, preferably C₁₋₆ ; fluoroalkyl, preferably fluoroethyl, difluoroethyl, fluoroisopropyl, trifluoroisopropyl; aminosulfonyl which may be substituted by alkyl, preferably C₁₋₅ ; hydroxy; or benzyl which may be substituted by up to three substitutents independently selected from alkyl (preferably C₁₋₄), alkoxy (preferably C₁₋₄), nitro, halogen and CF₃ ;

R² is hydrogen; alkyl, preferably C_(1-4;) fluoroalkyl, preferably fluoroethyl, difluoroethyl, fluoroisopropyl, trifluoroisopropyl; or cycloalkyl, preferably C₃₋₋₇ ;

R¹ --N-R² together may be a 5- or 6-membered heterocycle which may be unsubstituted or substituted with one or more substitutents independently selected from alkyl (preferably C₁₋₄), N(CH₃)₂, nitro, CONH₂ and COOEt;

A is a valyl, isoleucyl, leucyl, allo-isoleucyl, 2,2-dimethylglycyl, 2-cyclopropylglycyl, 2-cyclopentylglycyl, 3-tert-butylalanyl, 2-tert-butylglycyl, 3-cyclohexylalanyl, 2-ethylglycyl, 2-cyclohexylglycyl, norleucyl or norvalyl residue;

B is a N-alkyl-valyl, -norvalyl, -leucyl, -isoleucyl, -2-tert-butylglycyl, -3-tert-butylalanyl, -2-ethylglycyl, -2-cyclopentylglycyl, -2-cyclopentylglycyl, norleucyl or -2-cyclohexylglycyl residue where N-alkyl is preferably N-methyl or N-ethyl;

D is a prolyl, homoprolyl, hydroxyprolyl, 3,4-dehydroprolyl, 4-fluoroprolyl, 3-methylprolyl, 4-methylprolyl, 5-methylprolyl, azetidine-2-carbonyl, 3,3-dimethylprolyl, 4,4-difluoroprolyl, oxazolidine-4-carbonyl or thiazolidine-4-carbonyl residue;

E is a prolyl, homoprolyl, hydroxyprolyl, 3,4-dehydroprolyl, 4-fluoroprolyl, 3-methylprolyl, 4-methylprolyl, 5-methylprolyl, azetidine-2-carbonyl, 3,3-dimethylprolyl, 4,4-difluoroprolyl, oxazolidine-4-carbonyl or thiazolidine-4-carbonyl residue;

F and G are independently selected from the group consisting of prolyl, homoprolyl, hydroxyprolyl, thiazolidinyl-4-carbonyl, 1-aminopentyl -1-carbonyl, valyl, 2-tert-butylglycyl, isoleucyl, leucyl, 3-cyclohexylalanyl, phenylalanyl, N-methylphenylalanyl, tetrahydroisoquinolyl -2-carbonyl, 3-thiazolylalanyl, 3-thienylalanyl, histidyl, 1-aminoindyl-1-carbonyl, 3-pyridylalanyl, 2-cyclohexylglycyl, norleucyl, norvalyl, neopentylglycyl, tryptophanyl, glycyl, alanyl, β-alanyl and 3-naphthylalanyl residues;

x is hydrogen, alkyl (preferably C₁₋₅), cycloalkyl (preferablyl C₃₋₇), --CH₂ -cyclohexyl or arylalkyl (preferably benzyl or phenethyl);

s, t and u are independently 0 or 1; and

K is hydroxy, alkoxy (preferably C₁₋₄), phenoxy, benzyloxy or a substituted or unsubstituted amino moiety;

and the salts thereof with physiologically tolerated acids.

This invention also provides methods for preparing the compounds of formula I, pharmaceutical compositions containing such compounds together with a pharmaceutically acceptable carrier and methods for using same for treating cancer in mammals.

One subclass of compounds of this invention includes compounds of formula I wherein R¹ --N--R² is a pyrrolidinyl or piperidinyl residue which may be unsubstituted or substituted with one or more substituents which may independently be selected from alkyl (preferably C₁₋₄), N(CH₃)₂, nitro, oxo, CONH₂ and COOEt;

Another subclass of compounds of this invention includes compounds of formula I wherein K is an amino moiety of the formula R⁵ --N--R⁶ wherein

R⁵ is hydrogen, or hydroxy, or C₁₋₇ alkoxy, or benzyloxy (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, phenoxy, benzoxy, halogen, C₁₋₄ -alkyl, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or phenyloxy (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, phenoxy, benzoxy, halogen, C₁₋₄ -alkyl, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or C₁₋₁₂ -alkyl (which may be substituted by one or more fluoro atoms), or C₃₋₇ -cycloalkyl, or benzyl (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, phenoxy, benzoxy, halogen, C₁₋₄ -alkyl, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂);

R⁶ is hydrogen, or C₁₋₁₂ alkyl (which may be substituted by one or more fluoro atoms), or --(CH₂)_(v) ,--C₃₋₇ -cycloalkyl (v=0,1,2, or 3), or norephedryl, or norpseudoephedryl, or quinolyl, or pyrazyl, or --CH₂ -benzimidazolyl, or adamantyl, or --CH₂ -adamantyl, or alpha-methyl-benzyl, or alpha-dimethylbenzyl, or

--(CH₂)_(v),-phenyl (v=0,1,2,or 3; which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, phenoxy, benzoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or

--(CH₂)_(m) -naphthyl (m=0 or 1; which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or

--(CH₂)_(w) -benzhydryl (w=0,1, or 2; which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or

biphenyl (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or pyridyl (which may be substituted by up to two substitutents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or picolyl (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or

--CH₂ --CH₂ -pyridyl (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or benzothiazolyl (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or benzoisothiazolyl (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or benzopyrazolyl (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or benzoxazolyl (which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or

--(CH₂)_(m) -fluorenyl (m=0 or 1; which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or pyrimidyl (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or

--(CH₂)_(m),-indanyl (m=0 or 1; which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C1-4-alkyl which may form a cyclic system, cyano, hydroxy, N(CH₃)₂, COOMe, COOEt, COOiPr, or COONH₂), or

--(CH₂ CH₂ O)_(y) --CH₃ (y=0,1,2,3,4, or 5), or

--(CH₂ CH₂ O)_(y) --CH₂ CH₃ (y=0,1,2,3,4, or 5), or

--NH--C₆ H₅ (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or

--NCH₃ --C₆ H₅ (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or

--NH--CH₂ --C₆ H₅ (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or

--NCH₃ --CH₂ --C₆ H₅ (which may be substituted by up to two substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, halogen, C₁₋₄ -alkyl which may form a cyclic system, cyano, hydroxy, COOMe, COOEt, COOiPr, or COONH₂), or

5-membered heteroaryl which may be substituted by up to three substituents which may independently be CF₃, nitro, C₁₋₇ alkylsulfonyl, C₁₋₄ alkoxy, thiomethyl, thioethyl, picolyl, acetyl, C₃₋₆ -cycloalkyl, thiophenyl, --CH₂ --COOEt, C₃₋₄ -alkylen group forming a bicyclic system with the heterocycle, phenyl (which may be substituted by up to three substituents which may independently be nitro, CF₃, CN, halogen, or C₁₋₄ -alkyl), benzyl (which may be substituted by up to three substituents which may independently be nitro, CF₃, halogen, C₁₋₄ -alkyl, C₁₋₇ -alkylsulfonyl, cyano, hydroxy, C₁₋₄ -dialkylamino), or

--CHR⁷ -5-membered heteroaryl (which may be substituted by up to two subsituents which may independently be CF₃, nitro, cyano, halogen, COOMe, COOEt, COOiPr, CONH₂, C₁₋₄ -alkyl, C₁₋₄ -alkoxy, phenyl, benzyl, naphthyl, or C₁₋₇ -alkylsulfonyl R⁷ =hydrogen, linear or branched C₁₋₅ alkyl, benzyl; or R⁷ and R⁵ together form a group --(CH₂)₃ --or --(CH₂)₄ --!).

This subclass includes compounds of formula I wherein s, t and u are independently 0 or 1; R¹, R² and X are lower alkyl, A is a lower alkyl amino acid, B is a N-loweralkylated lower alkyl amino acid; D,E,F,G and K are as previously defined. With the foregoing in mind, three sets of such compounds can thus be depicted by the following formulas II, III, and IV:

    R.sup.1 R.sup.2 N-CXH-CO-A-B-Pro-Pro-F-G-K                 II

    R.sup.1 R.sup.2 N-CXH-CO-A-B-Pro-Pro-F-K                   III

    R.sup.1 R.sup.2 N-CXH-CO-A-B-Pro-Pro-K                     IV

--CHR⁷ -5-membered heteroaryl may for example be represented by one of the following residues: ##STR1## --NR⁵ CHR⁷ --5-membered heteroaryl may for example be represented by the following residues: ##STR2## 5-membered heteroaryl may for example be represented by the following residues: ##STR3##

In another subclass of compounds of this invention R⁵ --N--R⁶ together may form structures selected from the group consisting of ##STR4## which may be unsubstituted or substituted with one or more substituents independently selected from the group consisting of CF₃, nitro, halogen, oxo, cyano, formyl, N,N-dimethylamino, C₁₋₆ -alkyl, C₃₋₆ -cycloalkyl, C₃₋₄ -alkylen group forming a bicyclic system with the heterocycle, C₁₋₄ -alkoxy, phenoxy, benzoxy, naphthyl, pyrimidyl, COOEt, pyrrolidinyl, piperidinyl, thienyl, pyrrolyl, CH₂ --CO--NCH(CH₃)₂, --CH₂ --CO--N(CH₂)₄, --CH₂ --CO--N(CH2)₄ 0, benzyl (which may be substituted by up to three substituents independently selected from the group consisting of nitro, halogen, CF₃, thiomethyl or the corresponding sulfoxide or sulfone, thioethyl or the corresponding sulfoxide or sulfone, C₁₋₄ -alkyl, and C₁₋₄ -alkoxy).

Still another subclass of compounds of this invention includes for example compounds of formula I wherein s, t and u are 1 and K is a hydroxy, alkoxy, phenoxy or benzyloxy moiety.

Yet another subclass of compounds of this invention includes for example compounds of formula I wherein s and t are 1, u is 0 and K is a hydroxy, alkoxy, phenoxy or benzyloxy moiety.

Another subclass of compounds of this invention includes for example compounds of formula I wherein s is 1, t and u are 0 and K is a hydroxy, alkoxy, phenoxy or benzyloxy moiety.

These examples illustrate but do not limit the scope of the present invention.

The peptides of the formula I are composed preferably of L-amino acids but they may contain one or more D-amino acids.

The new compounds may be present as salts with physiologically tolerated acids such as: hydrochloric acid, citric acid, tartaric acid, lactic acid, phosphoric acid, methanesulfonic acid, acetic acid, formic acid, maleic acid, fumaric acid, malic acid, succinic acid, malonic acid, sulfuric acid, L-glutamic acid, L-aspartic acid, pyruvic acid, mucic acid, benzoic acid, glucuronic acid, oxalic acid, ascorbic acid and acetylglycine.

The novel compounds can be prepared by known methods of peptide chemistry. Thus, the peptides can be assembled sequentially from amino acids or by linking suitable small peptide fragments. In the sequential assemblage, starting at the C terminus the peptide chain is extended stepwise by one amino acid each time. In fragment coupling it is possible to link together fragments of different lengths, and the fragments in turn can be obtained by sequential assemblage from amino acids or themselves by fragment coupling.

Both in the sequential assemblage and in the fragment coupling it is necessary to link the units by forming an amide linkage. Enzymatic and chemical methods are suitable for this.

Chemical methods for forming the amide linkage are described in detail by Mueller, Methoden der organischen Chemie Vol. XV/2, pp 1 to 364, Thieme Verlag, Stuttgart, 1974; Stewart, Young, Solid Phase Peptide Synthesis, pp 31 to 34, 71 to 82, Pierce Chemical Company, Rockford, 1984; Bodanszky, Klausner, Ondetti, Peptide Synthesis, pp 85 to 128, John Wiley & Sons, New York, 1976 and other standard works on peptide chemistry. Particular preference is given to the azide method, the symmetric and mixed anhydride method, in situ generated or preformed active esters, the use of urethane protected N-carboxy anhydrides of amino acids and the formation of the amide linkage using coupling reagents (activators, especially dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC ), 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI), n-propanephosphonic anhydride (PPA), N,N-bis(2-oxo-3-oxazolldinyl)-amidophosphoryl chloride (BOP-Cl), bromo-tris-pyrrolidinophosphonium hexafluorophosphate (PyBrop), diphenylphosphoryl azide (DPPA), Castro's reagent (BOP, PyBop), 0-benzotriazolyl-N,N,N', N'-tetramethyluronium salts (HBTU), diethylphosphoryl cyanide (DEPCN), 2,5-diphenyl-2,3-dihydro-3-oxo-4-hydroxythiophene dioxide (Steglich's reagent; HOTDO) and 1,1'-carbonyldiimidazole (CDI). The coupling reagents can be employed alone or in combination with additives such as N,N-dimethyl-4-aminopyridine (DMAP), N-hydroxy-benzotriazole (HOBt), N-hydroxybenzotriazine (HOOBt), Azabenzotriazole, N-hydroxysuccinimide (HOSu) or 2-hydroxypyridine.

Whereas it is normally possible to dispense with protective groups in enzymatic peptide synthesis, reversible protection of reactive groups not involved in formation of the amide linkage is necessary for both reactants in chemical synthesis. Three conventional protective group techniques are preferred for the chemical peptide synthesis: the benzyloxycarbonyl (Z), the t-butoxycarbonyl (Boc) and the 9-fluorenylmethoxycarbonyl (Fmoc) techniques. Identified in each case is the protective group on the alpha-amino group of the chain-extending unit. A detailed review of amino-acid protective groups is given by Mueller, Methoden der organischen Chemie Vol. XV/1, pp 20 to 906, Thieme Verlag, Stuttgart, 1974. The units employed for assembling the peptide chain can be reacted in solution, in suspension or by a method similar to that described by Merrifield in J. Amer. Chem. Soc. 85 (1963) 2149. Particularly preferred methods are those in which peptides are assembled sequentially or by fragment coupling using the Z, Boc or Fmoc protective group technique, with one of the reactants in the said Merrifield technique being bonded to an insoluble polymeric support (also called resin hereinafter). This typically entails the peptide being assembled sequentially on the polymeric support using the Boc or Fmoc protective group technique, the growing peptide chain being covalently bonded at the C terminus to the insoluble resin particles (cf. FIG. 1 and 2). This procedure makes it possible to remove reagents and byproducts by filtration, and thus recrystallization of intermediates is unnecessary.

The protected amino acids can be linked to any suitable polymers, which merely have to be insoluble in the solvents used and to have a stable physical form which makes filtration easy. The polymer must contain a functional group to which the first protected amino acid can be firmly attached by a covalent bond. Suitable for this purpose are a wide variety of polymers, eg. cellulose, polyvinyl alcohol, polymethacrylate, sulfonated polystyrene, chloromethylated styrene/divinylbenzene copolymer (Merrifield resin), 4-methylbenzhydrylamine resin (MBHA-resin), phenylacetamidomethyl-resin (Pam-resin), p-benzyloxy-benzyl-alcohol-resin, benzhydryl-amine-resin (BHA-resin), 4-(hydroxymethyl)-benzoyloxy-methyl-resin, the resin of Breipohl et al. (Tetrahedron Letters 28 (1987) 565; supplied by BACHEM), 4-(2,4-di-methoxyphenylaminomethyl)phenoxy-resin (supplied by Novabiochem) or o-chlorotrityl-resin (supplied by Biohellas).

Suitable for peptide synthesis in solution are all solvents which are inert under the reaction conditions, especially water, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetonitrile, dichloromethane (DCM), 1,4-dioxane, tetrahydrofuran (THF), N-methyl-2-pyrrolidone (NMP) and mixtures of the said solvents. Peptide synthesis on the polymeric support can be carried out in all inert organic solvents in which the amino-acid derivatives used are soluble. However, preferred solvents additionally have resin-swelling properties, such as DMF, DCM, NMP, acetonitrile and DMSO, and mixtures of these solvents. After synthesis is complete, the peptide is cleaved off the polymeric support. The conditions under which cleavage off the various resin types is possible are disclosed in the literature. The cleavage reactions most commonly used are acid- and palladium-catalyzed, especially cleavage in liquid anhydrous hydrogen fluoride, in anhydrous trifluormoethanesulfonic acid, in dilute or concentrated trifluoroacetic acid, palladium-catalyzed cleavage in THF or THF-DCM mixtures in the presence of a weak base such as morpholine or cleavage in acetic acid/dichloromethane/trifluoroethanol mixtures. Depending on the chosen protective groups, these may be retained or likewise cleaved off under the cleavage conditions. Partial deprotection of the peptide may also be worthwhile when certain derivatization reactions are to be carried out. Peptides dialkylated at the N-terminus can be prepared either by coupling on the appropriate N,N-di-alkylamino acids in solution or on the polymeric support or by reductive alkylation of the resin-bound peptide in DMF/1% acetic acid with NaCNBH₃ and the appropriate aldehydes. The various non-naturally occurring amino acids as well as the various non-amino acid moieties disclosed herein may be obtained from commercial sources or synthesized from commercially-available materials using methods known in the art. For example, amino acids building blocks with R₁ and R₂ moieties can be prepared according to E. Wuensch, Houben Weyl, Meth. d. Org. Chemie, Bd. XV, 1, p. 306 following, Thieme Verlag Stuttgart 1974 and Literature cited therein. Peptides with gamma- or delta-lactam bridges can be prepared by incorporating the appropriate lactam-bridged dipeptide units (R. Freidinger, J. Org. Chem. (1982) 104-109) into the peptide chain. Peptides with thiazole-, oxazol-, thiazolin- or oxazolin-containing dipeptide building blocks can be prepared by incorporating the appropriate dipeptidic units (P. Jouin et al., Tetrahedron Letters (1992), 2807-2810; P. Wipf et al., Tetrahedron Letters (1992), 907-910; W.R. Tully, J. Med. Chem. (1991), 2065; Synthesis (1987), 235) into the peptide chain.

The compounds of this invention may be used to inhibit or otherwise treat solid tumors (e.g. tumors of the lung, breast, colon, prostate, bladder, rectum, or endometrial tumors) or hematological malignancies (e.g. leukemias, lymphomas) by administration of the compound to the mammal. Administration may be by any of the means which are conventional for pharmaceutical, preferably oncological, agents, including oral and parenteral means such as subcutaneously, intravenously, intramuscularly and intraperitoneally. The compounds may be administered alone or in the form of pharmaceutical compositions containing a compound of formula I together with a pharmaceutically accepted carrier appropriate for the desired route of administration. Such pharmaceutical compositions may be combination products, i.e., may also contain other therapeutically active ingredients.

The dosage to be administered to the mammal will contain an effective tumor-inhibiting amount of active ingredient which will depend upon conventional factors including the biological activity of the particular compound employed; the means of administration; the age, health and body weight of the recipient; the nature and extent of the symptoms; the frequency of treatment; the administration of other therapies; and the effect desired. A typical daily dose will be about 0.05 to 100 milligrams per kilogram of body weight, preferably 0.1 to 10 milligrams, on oral administration and about 0.01 to 100 milligrams per kilogram of body weight, preferably 0.05 to 50 milligrams, on parenteral administration.

The novel compounds can be administered in conventional solid or liquid pharmaceutical administration forms, e.g. uncoated or (film-)coated tablets, capsules, powders, granules, suppositories or solutions. These are produced in a conventional manner. The active substances can for this purpose be processed with conventional pharmaceutical aids such as tablet binders, fillers, preservatives, tablet disintegrants, flow regulators, plasticizers, wetting agents, dispersants, emulsifiers, solvents, sustained release compositions, antioxidants and/or propellant gases (cf. H. Sucker et al.: Pharmazeutische Technologie, Thieme- Verlag, Stuttgart, 1978). The administration forms obtained in this way normally contain 1-90% by weight of the active substance.

The following examples are intended to illustrate the invention. The proteinogenous amino acids are abbreviated in the examples using the known three-letter code. Other meanings are: TFA=trifluoroacetic acid, Ac=acetic acid, Bu=butyl, Et=ethyl, Me=methyl, Bzl=benzyl, Nal=3-naphthylalanine, Cha=3-cyclohexylalanine, Npg=neopentylglycine, Abu=2-amino butyryl, Dab=2,4-diaminobutyryl. iPr=isopropyl.

A. General procedures

I. The peptides claimed in claim 1 are either synthesized by classical solution synthesis using standard Z- and Boc-methodology as described above or by standard methods of solid-phase synthesis on a completely automatic model 431A synthesizer supplied by APPLIED BIOSYSTEMS. The apparatus uses different synthetic cycles for the Boc and Fmoc protective group techniques.

    ______________________________________                                         a) Synthetic cycle for the Boc protective group technique                      ______________________________________                                         1.    30% trifluoroacetic acid in DCM                                                                       1 × 3 min                                   2.    50% trifluoroacetic acid in DCM                                                                       1 × 1 min                                   3.    DCM washing            5 × 1 min                                   4.    5% diisopropylethylamine in DCM                                                                       1 × 1 min                                   5.    5% diisopropylethylamine in NMP                                                                       1 × 1 min                                   6.    NMP washing            5 × 1 min                                   7.    Addition of preactivated protected                                             amino acid (DCC and 1 equivalent of                                            HOBt in NMP/DCM);                                                              Peptide coupling (1st part)                                                                           1 × 30 min                                  8.    Addition of DMSO to the reaction                                               mixture until it contains 20% DMSO                                             by volume                                                                      Peptide coupling (2nd part)                                                                           1 × 16 min                                  9.    Addition of 3.8 equivalents of                                                 diisopropylethylamine to the reaction                                          mixture                                                                        Peptide coupling (3rd part)                                                                           1 × 7 min                                   10.   DCM washing            3 × 1 min                                   11.   if conversion is incomplete,                                                   repetition of coupling (back to 6.)                                      12.   10% acetic anhydride,                                                          5% diisopropylethylamine in DCM                                                                       1 × 2 min                                   13.   10% acetic anhydride in DCM                                                                           1 × 4 min                                   14.   DCM washing            4 × 1 min                                   15.   back to 1.                                                               ______________________________________                                    

BOP-Cl and PyBrop were used as reagents for coupling of the amino acid following N-methylamino acids. The reaction times were correspondingly increased. In solution synthesis, the use of either Boc-protected amino acid NCAs (N-tert.-butyloxycarbonyl-amino acid-N-carboxy-anhydrides) or Z-protected amino acid NCAs (N-benzyloxycarbonyl-amino acid-N-carboxy-anhydrides) respectively is most advantageous for this type of coupling.

    ______________________________________                                         b) Synthetic cycle for the Fmoc protective group technique                     ______________________________________                                         1.     DMF washing          1 × 1 min                                    2.     20% piperidine in DMF                                                                               1 × 4 min                                    3.     20% piperidine in DMF                                                                               1 × 16 min                                   4.     DMF washing          5 × 1 min                                    5.     Addition of the preactivated                                                   protected amino acid (activation                                               by 1 equivalent of TBTU and                                                    5 equivalents of DIPEA in DMF);                                                Peptide coupling     1 × 61 min                                   6.     DMF washing          3 × 1 min                                    7.     if conversion is incomplete,                                                   repetition of coupling (back to 5.)                                     8.     10% acetic anhydride in DMF                                                                         1 × 8 min                                    9.     DMF washing          3 × 1 min                                    10.    back to 2.                                                              ______________________________________                                    

BOP-Cl and PyBrop were used as reagents for coupling on the amino acid following the N-methylamino acids. The reaction times were correspondingly increased.

II. Reductive alkylation of the N terminus

The peptide-resin prepared as in AIa or AIb was deprotected at the N terminus (steps 2-4 in AIb or 1-6 in AIa) and then reacted with a 3-fold molar excess of aldehyde or ketone in DMF/1% acetic acid with addition of 3 equivalents of NaCNBH₃. After reaction was complete (negative Kaiser test) the resin was washed several times with water, isopropanol, DMF and dichloromethane.

III. Workup of the peptide-resins obtained as in Ia and II

The peptide-resin was dried under reduced pressure and transferred into a reaction vessel of a TEFLON HF apparatus (supplied by PENINSULA). Addition of a scavenger, preferably anisole (1 ml/g of resin), and in the case of tryptophan-containing peptides of a thiol to remove the indolic formyl group, preferably ethanedithiol (0.5 ml/g of resin), was followed by condensing in hydrogen fluoride (10 ml/g of resin) while cooling with liquid N₂. The mixture was left to warm to 0° C. and stirred at this temperature for 45 min. The hydrogen fluoride was then stripped off under reduced pressure, and the residue was washed with ethyl acetate in order to remove remaining scavenger. The peptide was extracted with 30% acetic acid and filtered, and the filtrate was lyophilized.

IV. Work-up of the peptide-resins obtained as in Ib and II

The peptide-resin was dried under reduced pressure and then subjected to one of the following cleavage procedures, depending on the amino-acid composition (Wade, Tregear, Howard Florey Fmoc Workshop Manual, Melbourne 1985).

Cleavage conditions:

    ______________________________________                                         TFA          Scavenger  Reaction time                                          ______________________________________                                         1.     95%       5% water   1.5 h                                              2.     95%       5% ethanethiol/                                                                           1.5 h                                                               anisol (1:3)                                                  ______________________________________                                    

The suspension of the peptide-resin in the suitable TFA mixture was stirred at room temperature for the stated time and then the resin was filtered off and washed with TFA and DCM. The filtrate and the washings were concentrated, and the peptide was precipitated by addition of diethyl ether. After cooling in an ice bath, the precipitate was filtered off, taken up in 30% acetic acid and lyophilized.

V. When an o-chlorotrityl-resin (supplied by Biohellas) is used, the suspension of the peptide-resin in an acetic acid/trifluoroethanol/dichloromethane mixture (1:1:3) is stirred at room temperature for 1 h. The resin is then filtered off with suction and thoroughly washed with the cleavage solution. The combined filtrates are concentrated in acuo and treated with water. The precipitated solid is removed by filtration or centrifugation, washed with diethyl ether and dried under reduced pressure.

VI. Purification and characterization of the peptides

Purification was carried out by gel chromatography (SEPHADEX G-10, G-15/10% HOAc, SEPHADEX LH20/MeOH) with or without subsequent medium pressure chromatography (stationary phase: HD-SIL C-18, 20-45 mikron, 100 Angstrom; mobile phase: gradient with A=0.1% TFA/ MeOH, B=0.1% TFA/water).

The purity of the resulting products was determined by analytical HPLC (stationary phase: 100 2.1 mm VYDAC C-18, 5 l, 300 A; mobile phase: acetonitrile-water gradient, buffered with 0.1% TFA, 40° C.).

Characterization was by amino-acid analysis and fast atom bombardment mass spectroscopy.

B. Specific procedures

EXAMPLE 1

(SEQ ID NO: 1)

N,N-Dimethyl-Val-Val-N-methyl-Val-Pro-Pro-Val-Phe-NH₂

1.98 g of Fmoc-RINK-resin (substitution 0.46 mmol/g), corresponding to a batch size of 0.84 mmol, were reacted as in AIb with 1.26 mmol each of

Fmoc-Phe-OH

Fmoc-Val-OH

Fmoc-Pro-OH

Fmoc-Pro-OH

Fmoc-N-methyl-Val-OH

Fmoc-Val-OH

Fmoc-Val-OH

The amino acid following the N-methylamino acid was coupled on with PyBrop as coupling reagent. After the iterative synthetic cycles were completed, the peptide-resin underwent N-terminal deprotection (steps 2-4 in AIb), and was further reacted with aqueous formaldehyde solution as in AII and then dried under reduced pressure. The resulting resin was subjected to TFA cleavage as in AIV. The crude product (590 mg) was purified by gel filtration (SEPHADEX-LH-20). The yield was 295 mg.

EXAMPLE 1 can also be prepared via classical solution phase methodology. The synthesis of N,N-Dimethyl-Val-Val-N-Methyl-Val-Pro-Pro-Val-Phe-NH₂ and its various intermediates is described in the following paragraph.

a) Z-MeVal-Pro-OMe

66.25 g (250 mmol) Z-MeVal-OH were dissolved in 250 ml dry dichloromethane. After addition of 36.41 ml (262.5 mmol) triethylamine , the reaction mixture was cooled to -25° C. and 32.27 ml (262.5 mmol) pivaloyl chloride were added.

After stirring for 2,5 h, 41.89 g (250 mmol) H-Pro-OMe×HCl in 250 ml dichloromethane, neutralized with 36.41 ml (262.5 mmol) triethylamine at 0° C., were added to the reaction mixture. Stirring continued for 2 h at -25° C. and overnight at room temperature. The reaction mixture was diluted with dichloromethane and thoroughly washed with saturated aqueous NaHCO₃ solution (3×), water (1×), 5% citric acid (3×) and saturated NaCl solution. The organic phase was dried over sodium sulfate and evaporated to dryness. The residue (91.24 g) was stirred with petroleum ether overnight and filtered. 62.3 g of product were obtained.

b) H-MeVal-Pro-OMe

48.9 g (130 mmol) Z-MeVal-Pro-OMe were dissolved in 490 ml methanol. After addition of 10.9 ml (130 mmol) concentrated hydrochloric acid and 2.43 g 10 % Palladium/charcoal, the reaction mixture was hydrogenated. Filtration and evaporation to dryness yielded 36.43 g of the product.

c) Z-Val-MeVal-Pro-OMe

18.1 g (65 mmol) H-MeVal-Pro-OMe, 21.6 g (78 mmol) Z-Val-N-carboxyanhydride and 22.8 ml (130 mmol) diisopropylethylamine were stirred in 110 ml DMF at 40° C. for 2 d. After evaporation of DMF, dichloromethane was added and the organic phase washed with saturated aqueous NaHCO₃ solution (3×), water (1×), 5% citric acid (3×) and saturated NaCl solution. The organic phase was dried over sodium sulfate and evaporated to dryness. The product (29.3 g) was obtained as a viscous oil.

d) H-Val-MeVal-Pro-OMe

29.3 g (61.6 mmol) of Z-Val-MeVal-Pro-OMe were dissolved in 230 ml methanol. After addition of 1.15 g 10% Palladium/charcoal, the reaction mixture was hydrogenated. Filtration and evaporation to dryness yielded 21.96 g of the product.

e) Z-Val-Val-MeVal-Pro-OMe

15.29 g (61 mmol) Z-Val-OH and 21.96 g (61 mmol) H-Val-MeVal-Pro-OMe were dissolved in 610 ml dichloromethane and cooled to 0° C. After addition of 8.16 ml (73.2 mmol) N-Methylmorpholine, 2.77 g (20.3 mmol) HOBt and 11.74 g (61 mmol) EDCI, the reaction mixture was stirred overnight at room temperature, diluted with dichloromethane and thoroughly washed with saturated aqueous NaHCO₃ solution (3×), water (1×), 5% citric acid (3×) and saturated NaCl solution. The organic phase was dried over sodium sulfate and evaporated to dryness to yield 31.96 g of the product.

f) Z-Val-Val-MeVal-Pro-OH

31.96 g (57 mmol) Z-Val-Val-MeVal-Pro-OMe were dissolved in 250 ml methanol. 102.6 ml of a 1 N LiOH solution was added and the mixture stirred overnight at room temperature. After addition of 500 ml water, the aqueous phase was washed three times with ethyl acetate, adjusted to pH 2 at 0° C. and extracted three times with ethyl acetate. The organic phase was dried over sodium sulfate and evaporated to dryness yielding 30.62 g of the desired product as a white solid.

g) Z-Val-Val-MeVal-Pro-Pro-Val-Phe-NH₂

25 g (43.3 mmol) Z-Val-Val-MeVal-Pro-OH and 15.59 g (43.3 mmol) H-Pro-Val-Phe-NH₂ were suspended in 430 ml of dry dichloromethane. After cooling to 0° C., 5.81 ml (52 mmol) N-methylmorpholine, 1.97 g (15 mmol) HOBt and 8.33 g (43.3 mmol) EDCI were added and the reaction mixture stirred overnight at room temperature. The solvents were evaporated, the residue dissolved in 640 ml dichloromethane and thoroughly washed with saturated aqueous NaHCO₃ solution (4×), water (1×), 5% citric acid (3×) and saturated NaCl solution. The organic phase was dried over sodium sulfate and evaporated to dryness to yield 33.04 g of the product. The crude product was chromatographed on a silica gel column with 20% MeOH/Hexane. 18.32 g of the desired product were obtained.

h) N,N-Dimethyl-Val-Val-MeVal-Pro-Pro-Val-Phe-NH₂

18.32 g Z-Val-Val-MeVal-Pro-Pro-Val-Phe-NH₂ were dissolved in 80 ml methanol. 0.4 g 10% Pd/C were added under nitrogen atmosphere and the reaction mixture hydrogenated at room temperature for 4 h. After addition of 6.22 ml (81.24 mmol) of a 37% aqueous formaldehyde solution, hydrogenation was continued for 5 h. Filtration and evaporation of the solvent gave rise to 15.6 g of crude product. Further purification was achieved by dissolving the peptide in water, adjusting the pH to 2 and extracting the aqueous phase three times with ethyl acetate. The aqueous phase was then adjusted to pH 8-9 and extracted four times with ethyl acetate. The organic phase was washed with water and dried over sodium sulfate to yield 11.3 g of purified product as a white powder. The compound was characterized by fast atom bombardment mass spectrometry ( M+H!⁺ =797).

EXAMPLE 2

(SEQ ID NO: 2)

N,N-Dimethyl-Val-Val-N-Me-Val-Pro-{1- thiazol-(2)-yl!-2-phenyl}-ethylamide

4.11 g of Fmoc-Pro-p-alkoxybenzyl-alcohol-resin (substitution 0.73 mmol/g), corresponding to a batch size of 3 mmol, were reacted as in AIb with 4.5 mmol each of

Fmoc-N-MeVal-OH

Fmoc-Val-OH

Fmoc-Val-OH.

The amino acid following the N-methylamino acid was in this case reacted with double coupling using PyBrop or Bop-Cl with increased reaction times. After the synthesis was complete, the peptide-resin underwent N-terminal deprotection (steps 2-4 in AIb), and was further reacted with aqueous formaldehyde solution as in AII and then dried under reduced pressure. The resin obtained in this way was subjected to TFA cleavage as in AIV. The crude product (750 mg) was employed directly for the next coupling. 100 mg of this compound were reacted with 45 mg of (S)-2- l-amino-2-phenylethyl! thiazole and 230 mg of PyBop with the addition of 192 mikroL of DIPEA in DMF at room temperature for 2 d. The reaction mixture was purified by gel chromatography (Sephadex LH-20, methanol) and the product fractions were combined. 83 mg of product were obtained.

The following compounds were prepared and can be prepared according to examples 1 and 2:

3. Xaa Val Xan Pro Pro Val Phe

4. Xaa Val Xan Pro Pro Val Xac

5. Xaa Val Xan Pro Pro Val Xad

6. Xaa Val Xan Pro Pro Val Xae

7. Xaa Val Xan Pro Pro Val Xaf

8. Xaa Val Xan Pro Pro Val His NH₂

9. Xbo Val Xan Pro Pro Val Phe NH₂

10. Xaa Val Xan Pro Pro Val Xag NH₂

11. Xaa Val Xan Pro Pro Val Xah

12. Xaa Xbe Xan Pro Pro Val Trp NH₂

13. Xaa Val Xan Pro Pro Xai Phe NH₂

14. Xae Val Xan Pro Pro Ile Phe NH₂

15. Xaa Val Xan Pro Xal Val Phe NH₂

16. Xaa Val Xan Pro Xak Val Phe NH₂

17. Xaa Val Xan Xak Pro Val Phe NH₂

18. Xaa Val Xan Xal Pro Val Phe NH₂

19. Xaa Val Xao Pro Pro Val Phe NH₂

20. Xaa Val Xam Pro Pro Val Phe NH₂

21. Xaa Xap Pro Pro Val Phe NH₂

22. Xaa Xaq Pro Pro Val Phe NH₂

23. Xaa Ile Xan Pro Pro Val Phe NH₂

24. Xaa Xai Xan Pro Pro Val Phe NH₂

25. Xaa Leu Xan Pro Pro Val Phe NH₂

26. Xar Val Xan Pro Pro Val Phe NH₂

27. Xas Val Xan Pro Pro Val Phe NH₂

28. Xat Val Xan Pro Pro Val Phe NH₂

29. Xau Val Xan Pro Xal Val Phe NH₂

30. Xav Val Xan Pro Pro Val Phe NH₂

31. Xan Val Xan Pro Pro Val Phe NH₂

32. Xaw Val Xan Pro Pro Val Phe NH₂

33. Xax Vai Xan Pro Pro Val Phe NH₂

34. Xaa Val Xan Pro Pro Phe Phe NH₂

35. Xaz Val Xan Pro Pro Val Phe NH₂

36. Xba Val Xan Pro Pro Val Phe NH₂

37. Xaa Val Xan Pro Pro Val NH₂

38. Xaa Val Xan Pro Xbb

39. Xaa Val Xan Pro Xbc

40. Xaa Val Xan Pro Pro Xbd

41. Xax Val Xan Pro Pro Val NH₂

42. Xaw Val Xan Pro Pro Val NH₂

43. Xat Val Xan Pro Pro Val NH₂

44. Xaa Xai Xan Pro Pro Val NH₂

45. Xaa Val Xan Pro Pro Xal NH₂

46. Xaa Val Xan Xak Pro Val NH₂

47. Xaa Val Xan Pro Xak Val NH₂

48. Xaa Val Xan Pro Pro Val

49. Xav Val Xan Pro Pro Val NH₂

50. Xaa Val Xan Pro Pro NH₂

51. Xaa Val Xan Pro Pro

52. Xaa Val Xan Pro Xbf

53. Xaa Val Xan Xbb

54. Xaa Val Xan Xbc

55. Xaa Val Xan Xbg

56. Xaa Val Xan Xbh

57. Xaa Val Xan Xbi

58. Xaa Val Xan Xbk

59. Xaa Val Xan Xbl

60. Xaa Val Xan Xbm

61. Xaa Val Xan Xbn

62. Xax Val Xan Pro Pro NH₂

63. Xaw Val Xan Pro Pro NH₂

64. Xbo Val Xan Pro Pro NH₂

65. Xat Val Xan Pro Pro NH₂

66. Xaa Xai Xan Pro Pro NH₂

67. Xat Xai Xan Pro Pro NH₂

68. Xaa Xap Pro Pro NH₂

69. Xaa Xaq Pro Pro NH₂

70. Xav Val Xan Pro Pro NH₂

71. Xaa Xap Pro NH₂

72. Xaa Xaq Pro NH₂

73. Xaa Val Xan Pro

74. Xaa Val Xbp

75. Xaa Val Xbq

76. Xaa Val Xbr

77. Xaa Val Xbs

78. Xaa Val Xan Xbf

79. Xaa Val Xbt

80. Xaa Val Xbu

81. Xaa Val Xbv

82. Xaa Val Xbw

83. Xax Val Xan Pro NH₂

84. Xbo Val Xan Pro NH₂

85. Xav Val Xan Pro NH₂

86. Xaa Val Xan Pro Xbn

87. Xaa Val Xan Pro Xbg

88. Xaa Val Xan Pro Xbi

89. Xaa Val Xan Pro Xbl

90. Xbo Val Xan Pro Xbg

91. Xbo Val Xan Pro Xbl

92. Xbo Xbe Xan Pro Xbg

93. Xaa Val Xan Pro Xbx

94. Xaa Xbe Xan Pro Pro NH₂

95. Xby Val Xan Pro Pro Val Phe NH₂

96. Xed Val Xan Pro Pro Val Phe NH₂

97. Xee Val Xan Pro Pro Val Phe NH₂

98. Xef Val Xan Pro Pro Val Phe NH₂

99. Xbz Val Xan Pro Pro Val Phe NH₂

100. Xeg Val Xan Pro Pro Val Phe NH₂

101. Xca Val Xan Pro Pro Val Phe NH₂

102. Xcb Val Xan Pro Pro Val Phe NH₂

103. Xcb Val Xao Pro Pro Val Phe NH₂

104. Xcc Val Xan Pro Pro Val Phe NH₂

105. Xce Val Xan Pro Pro Val Phe NH₂

107. Xcg Val Xan Pro Pro Val Phe NH₂

108. Xch Val Xan Pro Pro Val Phe NH₂

109. Xci Val Xan Pro Pro Val Phe NH₂

110. Xck Val Xan Pro Pro Val Phe NH₂

111. Xcl Val Xan Pro Pro Val Phe NH₂

112. Xcm Val Xan Pro Pro Val Phe NH₂

113. Xcn Val Xan Pro Pro Val Phe NH₂

114. Xhn Val Xan Pro Pro Val Phe NH₂

115. Xho Val Xan Pro Pro Val Phe NH₂

116. Xhp Val Xan Pro Pro Val Phe NH₂

117. Xhq Val Xan Pro Pro Val Phe NH₂

118. Xby Val Xan Pro Pro Val NH₂

119. Xed Val Xan Pro Pro Val NH₂

120. Xee Val Xan Pro Pro Val NH₂

121. Xef Val Xan Pro Pro Val NH₂

122. Xbz Val Xan Pro Pro Val NH₂

123. Xeg Val Xan Pro Pro Val NH₂

124. Xca Val Xan Pro Pro Val NH₂

125. Xcb Val Xan Pro Pro Val NH₂

126. Xcc Val Xan Pro Pro Val NH₂

127. Xce Val Xan Pro Pro Val NH₂

128. Xcs Val Xan Pro Pro Val NH₂

129. Xch Val Xan Pro Pro Val NH₂

130. Xci Val Xan Pro Pro Val NH₂

131. Xck Val Xan Pro Pro Val NH₂

132. Xcl Val Xan Pro Pro Val NH₂

133. Xcm Val Xan Pro Pro Val NH₂

134. Xcn Val Xan Pro Pro Val NH₂

135. Xhn Val Xan Pro Pro Val NH₂

136. Xho Val Xan Pro Pro Val NH₂

137. Xhp Val Xan Pro Pro Val NH₂

138. Xhq Val Xan Pro Pro Val NH₂

139. Xby Val Xan Pro Pro NH₂

140. Xed Val Xan Pro Pro NH₂

141. Xee Val Xan Pro Pro NH₂

142. Xef Val Xan Pro Pro NH₂

143. Xbz Val Xan Pro Pro NH₂

144. Xeg Val Xan Pro Pro NH₂

145. Xca Val Xan Pro Pro NH₂

146. Xcb Val Xan Pro Pro NH₂

147. Xcc Val Xan Pro Pro NH₂

148. Xce Val Xan Pro Pro NH₂

149. Xcg Val Xan Pro Pro NH₂

150. Xch Val Xan Pro Pro NH₂

151. Xci Val Xan Pro Pro NH₂

152. Xck Val Xan Pro Pro NH₂

153. Xcl Val Xan Pro Pro NH₂

154. Xcm Val Xan Pro Pro NH₂

155. Xcn Val Xan Pro Pro NH₂

156. Xhn Val Xan Pro Pro NH₂

157. Xho Val Xan Pro Pro NH₂

158. Xhp Val Xan Pro Pro NH₂

159. Xhq Val Xan Pro Pro NH₂

160. Xaa Val Xan Pro Pro Val Xei

161. Xaa Val Xan Pro Pro Val Xem

162. Xaa Val Xan Pro Pro Val Xeo

153. Xaa Val Xan Pro Pro Val Xep

164. Xaa Val Xan Pro Pro Val Xeq

165. Xaa Val Xan Pro Pro Val Xex

166. Xaa Val Xan Pro Pro Val Xey

167. Xaa Val Xan Pro Pro Val Xfb

168. Xaa Val Xan Pro Pro Val Xfe

169. Xaa Val Xan Pro Pro Val Xfh

170. Xaa Val Xan Pro Pro Val Xfu

171. Xaa Val Xan Pro Pro Val Xfv

172. Xaa Val Xan Pro Pro Val Xft

173. Xaa Val Xan Pro Pro Val Xfw

174. Xaa Val Xan Pro Pro Val Xfx

175. Xaa Val Xan Pro Pro Val Xga

176. Xaa Val Xan Pro Pro Val Xgd

177. Xaa Val Xan Pro Pro Val Xgg

178. Xaa Val Xan Pro Pro Val Xgh

179. Xaa Val Xan Pro Pro Val Xgl

180. Xaa Val Xan Pro Pro Val Xgl

181. Xaa Val Xan Pro Pro Val Xgs

182. Xaa Val Xan Pro Pro Val Xgv

183. Xaa Val Xan Pro Pro Val Xhe

184. Xaa Val Xan Pro Pro Val Xgy

185. Xaa Val Xan Pro Pro Val Xhd

186. Xaa Val Xan Pro Pro Val Xhb

187. Xaa Val Xan Pro Pro Val Xhc

188. Xaa Val Xan Pro Pro Val Xhl

189. Xaa Val Xan Pro Pro Xeh

190. Xaa Val Xan Pro Pro Xen

191. Xaa Val Xan Pro Pro Xeo

192. Xaa Val Xan Pro Pro Xep

193. Xaa Val Xan Pro Pro Xeq

194. Xaa Val Xan Pro Pro Xer

195. Xaa Val Xan Pro Pro Xet

196. Xaa Val Xan Pro Pro Xeu

197. Xaa Val Xan Pro Pro Xes

198. Xaa Val Xan Pro Pro Xew

199. Xaa Val Xan Pro Pro Xez

200. Xaa Val Xan Pro Pro Xfc

201. Xaa Val Xan Pro Pro Xff

202. Xaa Val Xan Pro Pro Xfl

203. Xaa Val Xan Pro Pro Xfs

204. Xaa Val Xan Pro Pro Xfz

205. Xaa Val Xan Pro Pro Xgc

206. Xaa Val Xan Pro Pro Xgf

207. Xaa Val Xan Pro Pro Xgm

208. Xaa Val Xan Pro Pro Xgr

209. Xaa Val Xan Pro Pro Xgu

210. Xaa Val Xan Pro Pro Xgs

211. Xaa Val Xan Pro Pro Xgx

212. Xaa Val Xan Pro Pro Xha

213. Xaa Val Xan Pro Pro Xhk

214. Xaa Val Xan Pro Xek

215. Xaa Val Xan Pro Xen

216. Xaa Val Xan Pro Xer

217. Xaa Val Xan Pro Xep

218. Xaa Val Xan Pro Xeq

219. Xaa Val Xan Pro Xer

220. Xaa Val Xan Pro Xet

221. Xaa Val Xan Pro Xeu

222. Xaa Val Xan Pro Xes

223. Xaa Val Xan Pro Xfa

224. Xaa Val Xan Pro Xfd

225. Xaa Val Xan Pro Xfg

225. Xaa Val Xan Pro Xfl

227. Xaa Val Xan Pro Xfk

228. Xaa Val Xan Pro Xfm

229. Xaa Val Xan Pro Xfn

230. Xaa Val Xan Pro Xfo

231. Xaa Val Xan Pro Xfp

232. Xaa Val Xan Pro Xfq

233. Xaa Val Xan Pro Xfr

234. Xaa Val Xan Pro Xfy

235. Xaa Val Xan Pro Xgb

236. Xaa Val Xan Pro Xge

237. Xaa Val Xan Pro Xgk

238. Xaa Val Xan Pro Xgn

239. Xaa Val Xan Pro Xhi

240. Xaa Val Xan Pro Xgo

241. Xaa Val Xan Pro Xgp

242. Xaa Val Xan Pro Xgq

243. Xaa Val Xan Pro Xgt

244. Xaa Val Xan Pro Xgw

245. Xaa Val Xan Pro Xgz

246. Xaa Val Xan Pro Xhm

247. Xaa Xco Pro Pro Val Phe NH₂

248. Xaa Xcp Pro Pro Val Phe NH₂

249. Xaa Xcq Pro Pro Val Phe NH₂

250. Xaa Xcr Pro Pro Val Phe NH₂

251. Xaa Xcs Pro Pro Val Phe NH₂

252. Xaa Xct Pro Pro Val Phe NH₂

253. Xaa Xcu Pro Pro Val Phe NH₂

254. Xaa Xcw Pro Pro Val Phe NH₂

255. Xaa Xcv Pro Pro Val Phe NH₂

256. Xaa Xcx Pro Pro Val Phe NH₂

257. Xaa Xcy Pro Pro Val Phe NH₂

258. Xaa Xda Pro Pro Val Phe NH₂

259. Xaa Xdb Pro Pro Val Phe NH₂

260. Xaa Xdc Pro Pro Val Phe NH₂

261. Xaa Xdd Pro Pro Val Phe NH₂

262. Xaa Xdf Pro Pro Val Phe NH₂

263. Xaa Xdg Pro Pro Val Phe NH₂

264. Xaa Xdh Pro Pro Val Phe NH₂

265. Xaa Xco Pro Pro Val NH₂

266. Xaa Xcp Pro Pro Val NH₂

267. Xaa Xcq Pro Pro Val NH₂

268. Xaa Xcr Pro Pro Val NH₂

269. Xaa Xcs Pro Pro Val NH₂

270. Xaa Xct Pro Pro Val NH₂

271. Xaa Xcu Pro Pro Val NH₂

272. Xaa Xcw Pro Pro Val NH₂

273. Xaa Xcv Pro Pro Val NH₂

274. Xaa Xcx Pro Pro Val NH₂

275. Xaa Xcy Pro Pro Val NH₂

276. Xaa Xcz Pro Pro Val NH₂

277. Xaa Xda Pro Pro Val NH₂

278. Xaa Xdb Pro Pro Val NH₂

279. Xaa Xdc Pro Pro Val NH₂

280. Xaa Xde Pro Pro Val NH₂

281. Xaa Xdf Pro Pro Val NH₂

282. Xaa Xdg Pro Pro Val NH₂

283. Xaa Xdh Pro Pro Val NH₂

284. Xaa Xco Pro Pro NH₂

285. Xaa Xcp Pro Pro NH₂

286. Xaa Xcq Pro Pro NH₂

287. Xaa Xcr Pro Pro NH₂

288. Xaa Xcs Pro Pro NH₂

289. Xaa Xct Pro Pro NH₂

290. Xaa Xcu Pro Pro NH₂

291. Xaa Xcw Pro Pro NH₂

292. Xaa Xcv Pro Pro NH₂

293. Xaa Xcx Pro Pro NH₂

294. Xaa Xcy Pro Pro NH₂

295. Xaa Xcz Pro Pro NH₂

296. Xaa Xda Pro Pro NH₂

297. Xaa Xdb Pro Pro NH₂

298. Xaa Xdc Pro Pro NH₂

299. Xaa Xdd Pro Pro NH₂

300. Xaa Xdf Pro Pro NH₂

301. Xaa Xdg Pro Pro NH₂

302. Xaa Xdh Pro Pro NH₂

303. Xds Xan Pro Pro Val Phe NH₂

304. Xdt Xan Pro Pro Val Phe NH₂

305. Xdu Xan Pro Pro Val Phe NH₂

306. Xdv Xan Pro Pro Val Phe NH₂

307. Xdw Xan Pro Pro Val Phe NH₂

308. Xdx Xan Pro Pro Val Phe NH₂

309. Xdy Xan Pro Pro Val Phe NH₂

310. Xdz Xan Pro Pro Val Phe NH₂

311. Xea Xan Pro Pro Val Phe NH₂

312. Xeb Xan Pro Pro Val Phe NH₂

313. Xec Xan Pro Pro Val Phe NH₂

314. Xds Xan Pro Pro Val NH₂

315. Xdt xan Pro Pro Val NH₂

316. Xdu Xan Pro Pro Val NH₂

317. Xdv Xan Pro Pro Val NH₂

318. Xdw Xan Pro Pro Val NH₂

319. Xdx Xan Pro Pro Val NH₂

320. Xdy Xan Pro Pro Val NH₂

321. Xdz Xan Pro Pro Val NH₂

322. Xea Xan Pro Pro Val NH₂

323. Xeb Xan Pro Pro Val NH₂

324. Xed Xan Pro Pro Val NH₂

325. Xds Xan Pro Pro NH₂

326. Xdt Xan Pro Pro NH₂

327. Xdu Xan Pro Pro NH₂

328. Xdv Xan Pro Pro NH₂

329. Xdw Xan Pro Pro NH₂

330. Xdx Xan Pro Pro NH₂

331. Xdy Xan Pro Pro NH₂

332. Xdz Xan Pro Pro NH₂

333. Xea Xan Pro Pro NH₂

334. Xeb Xan Pro Pro NH₂

335. Xec Xan Pro Pro NH₂

336. Xds Val Pro Pro Val Phe NH₂

337. Xds Val Pro Pro NH₂

338. Xdv Val Pro Pro NH₂

339. Xds Xan Pro Xfy

340. Xdv Xan Pro Xfy

341. Xaa Val Xhf Pro Pro Val Phe NH₂

342. Xaa Val Xhg Pro Pro Val Phe NH₂

343. Xaa Val Xhh Pro Pro Val Phe NH₂

344. Xaa Val Xhf Pro Pro Val NH₂

345. Xaa Val Xhg Pro Pro Val NH₂

346. Xaa Val Xhh Pro Pro Val NH₂

347. Xaa Val Xhf Pro Pro NH₂

348. Xaa Val Xhg Pro Pro NH₂

349. Xaa Val Xhh Pro Pro NH₂

350. Xaa Val Xhf Pro Xfy

351. Xaa Val Xhg Pro Xfy

352. Xaa Val Xhh Pro Xfy

353. Xaa Val Xhf Pro Xgb

354. Xaa Val Xhg Pro Xgb

355. Xaa Val Xhh Pro Xgb

356. Xed Val Xan Pro Xfy

357. Xby Val Xan Pro Xfy

358. Xby Val Xan Pro Xhi

359. Xef Val Xan Pro Xfy

360. Xef Val Xan Pro Xhi

361. Xca Val Xan Pro Xfy

362. Xca Val Xan Pro Xhi

363. Xaa Val Xan Pro Xdp Phe NH₂

364. Xaa Val Xan Pro Xdq Phe NH₂

365. Xaa Val Xan Pro Xdr Phe NH₂

366. Xaa Val Xan Pro Xdp NH₂

367. Xaa val Xan Pro Xdq NH₂

368. Xaa Val Xan Pro Xdr NH₂

369. Xaa Val Xan Pro Pro Xdi NH₂

370. Xaa Val Xan Pro Pro Xcs NH₂

371. Xaa Val Xan Pro Pro Xct NH₂

372. Xaa Val Xan Pro Pro Xcu NH₂

373. Xaa Xcs Pro Pro Xdi NH₂

374. Xaa Xct Pro Pro Xdi NH₂

375. Xaa Xcs Pro Xdp Phe NH₂

376. Xaa Xct Pro Xdp Phe NH₂

377. Xaa Xcs Pro Xdp NH₂

378. Xaa Xct Pro Xdp NH₂

379. Xaa Xcs Pro Xdq NH₂

380. Xaa Xct Pro Xdq NH₂

381. Xaa Xcs Pro Xdr NH₂

382. Xaa Xct Pro Xdr NH₂

383. Xaa Val Xan Pro Pro Xdi NH₂

384. Xaa Val Xan Pro Pro Xdk NH₂

385. Xaa Val Xan Pro Pro Xdl NH₂

386. Xaa Val Xan Pro Pro Xdm NH₂

387. Xaa Val Xan Pro Pro Xdn NH₂

388. Xaa Val Xan Pro Pro Xdo NH₂

389. Xca Val Xan Pro Pro Phe Phe NH₂

390. Xby Val Xan Pro Pro Phe Phe NH₂

391. Xca Val Xan Pro Pro Phe Phe NH₂

392. Xef Val Xhf Pro Pro Xai Phe NH₂

393. Xef Val Xhf Pro Pro Xai Xah NH₂

394. Xef Val Xhf Pro Pro Xai Xag NH₂

395. Xef Val Xan Pro Xfy

396. Xef Val Xan Pro Xbg

397. Xef Val Xan Pro Xbh

398. Xef Val Xan Pro Xgn

399. Xca Xct Pro Xfy

400. Xaa Xai Xan Pro Pro Val Phe NH₂

401. Xaa Leu Xan Pro Pro Val Phe NH₂

402. Xaa Ile Xan Pro Pro Val Phe NH₂

403. Xaa Val Xan Pro Pro Xai Phe NH₂

404. Xaa Val Xan Pro Pro Leu Phe NH₂

405. Xaa Val Xan Pro Pro Ile Phe NH₂

406. Xaa Val Xan Pro Pro Val Dab NH₂

407. Xaa Val Xan Pro Pro Val Ala NH₂

408. Xaa Dab Xan Pro Pro Val Phe NH₂

409. Xaa Xab Xan Pro Pro Val NH₂

410. Xaa Dab Xan Pro Pro NH₂

411. Xht Val Xan Pro Pro Val Phe NH₂

412. Xhu Val Xan Pro Pro Val Phe NH₂

413. Xht Val Xan Pro Pro Val NH₂

413. (a). Xhu Val Xan Pro Pro Val NH₂

414. Xht Val Xan Pro Pro NH₂

415. Xhu Val Xan Pro Pro NH₂

416. Xaa Val Xhy Pro Pro Val Phe NH₂

417. Xaa Val Xhz Pro Pro Val Phe NH₂

418. Xaa Val Xhy Pro Pro Val NH₂

419. Xaa Val Xhz Pro Pro Val NH₂

420. Xaa Val Xhy Pro Pro NH₂

421. Xaa Leu Xhz Pro Pro NH₂

422. Xaa Val Xhy Xfy

423. Xaa Val Xhz Xfy

424. Xhv Val Xan Pro Pro Val Phe NH₂

425. Xhw Val Xan Pro Pro Val Phe NH₂

426. Xhx Val Xan Pro Pro Val Phe NH₂

427. Xhv Val Xan Pro Pro Val NH₂

428. Xhw Val Xan Pro Pro Val NH₂

429. Xhx Val Xan Pro Pro Val NH₂

430. Xhv Val Xan Pro Pro NH₂

431. Xhw Val Xan Pro Pro NH₂

432. Xhx Val Xan Pro Pro NH₂

433. Xaa Val Xan Pro Xia

434. Xaa Val Xan Pro Xib

435. Xaa Val Xan Pro Xic

436. Xaa Val Xan Pro Xid

437. Xaa Val Xan Pro Xie

438. Xby Val Xan Pro Xia

439. Xby Val Xan Pro Xib

440. Xby Val Xan Pro Xic

441. Xby Val Xan Pro Xid

442. Xby Val Xan Pro Xie

443. Xca Val Xan Pro Xia

444. Xca Val Xan Pro Xib

445. Xca Val Xan Pro Xic

446. Xca Val Xan Pro Xid

447. Xca Val Xan Pro Xie

448. Xed Val Xan Pro Xia

449. Xed Val Xan Pro Xib

450. Xed Val Xan Pro Xic

451. Xed Val Xan Pro Xld

452. Xed Val Xan Pro Xie

453. Xby Leu Xan Pro Xia

454. Xby Leu Xan Pro Xib

455. Xby Ile Xan Pro Xic

455. Xby Ile Xan Pro Xid

457. Xby Leu Xan Pro Xie

458. Xca Leu Xan Pro Xia

459. Xca Val Xao Pro Xib

460. Xca Val Xao Pro Xic

461. Xat Val Xhf Pro Xak Leu Phe NH₂

462. Xat Val Xhf Pro Xhr Leu Phe NH₂

463. Xed Val Xhf Pro Xak Leu Phe NH₂

464. Xed Val Xhf Pro Xhr Leu Phe NH₂

465. Xat Val Xhf Pro Xak Val NH₂

466. xat Val Xhf Pro Xhr Val NH₂

467. Xed Val Xhf Pro Xak Val NH₂

468. Xed Val Xhf Pro Xhr Val NH₂

469. Xat Val Xhf Pro Xak NH₂

470. Xat Val Xhf Pro Xhr NH₂

471. Xed Val Xhf Pro Xak NH₂

472. Xat Val Xhf Pro Xia

473. Xat Val Xhf Pro Xib

474. Xed Val Xhf Pro Xic

475. Xed Val Xhf Pro Xid

476. Xat Val Xhf Pro Xie

477. Xat Val Xhf Pro Xhs NH₂

478. Xed Val Xhf Pro Xhs NH₂

479. Xat Val Xhf Pro Xak Xfz

480. Xat Val Xhf Pro Xhr Xfz

481. Xed Val Xhf Pro Xak Xfz

482. Xed Val Xhf Pro Xhr Xfz

483. Xat Val Xhf Pro Xak Xbw

484. Xat Val Xhf Pro Xhr Xbw

485. Xed Val Xhf Pro Xak Xbw

486. Xed Val Xhf Pro Xhr Xbw

487. Xat Val Xhf Pro Xak Xer

488. Xat Val Xhf Pro Xhr Xer

489. Xed Val Xhf Pro Xak Xer

490. Xed Val Xhf Pro Xhr Xer

491. Xat Val Xhf Pro Xak Xgi

492. Xat Val Xhf Pro Xhr Xgi

493. Xed Val Xhf Pro Xak Xgi

494. Xed Val Xhf Pro Xhr Xgi

495. Xat Val Xhf Pro Xak Xif

496. Xat Val Xhf Pro Xhr Xif

497. Xed Val Xhf Pro Xak Xif

498. Xed Val Xhf Pro Xhr Xif

499. Xat Val Xhf Pro Xak Xig

500. Xat Val Xhf Pro Xhr Xig

501. Xed Val Xhf Pro Xak Xig

502. Xed Val Xhf Pro Xhr Xig

503. Xaa Val Xan Pro Pro Xlf

504. Xaa Val Xan Pro Xig

505. Xca Val Xan Pro Pro Xif

506. Xca Val Xan Pro Xlg

507. Xby Val Xan Pro Pro Xif

508. Xby Val Xan Pro Xig

509. Xed Val Xan Pro Pro Xif

510. Xed Val Xan Pro Xig

511. Xaa Leu Xan Pro Pro Xif

512. Xaa Leu Xan Pro Xig

513. Xca Leu Xan Pro Pro Xif

514. Xca Leu Xan Pro Xig

515. Xby Leu Xan Pro Pro Xif

516. Xby Leu Xan Pro Xig

517. Xed Leu Xan Pro Pro Xif

518. Xed Leu Xan Pro Xig

519. Xaa Lys Xan Pro Pro Val Phe NH₂

520. Xaa Lys Xan Pro Pro Val NH₂

521. Xaa Lys Xan Pro Pro NH₂

522. Xaa Lys Xan Pro Xfy

523. Xaa Xih Xan Pro Pro Val NH₂

524. Xaa Xih Xan Pro Pro NH₂

525. Xaa Xih Xan Pro Pro Val Phe NH₂

525. Xaa Val Xii Pro Pro Val Phe NH₂

527. Xaa Val Xii Pro Pro Val NH₂

528. Xaa Val Xii Pro Pro NH₂

529. Xaa Val Xan Pro Pro Val Lys NH₂

530. Xaa Val Xan Pro Xik

531. Xaa Val Xan Pro Pro Xil NH₂

532. Xaa Val Xbu

533. Xby Val Xbu

534. Xca Val Xbu

535. Xaa Val Xbv

536. Xby Val Xbv

537. Xca Val Xbv

538. Xaa Val Xan Pro Pro Xab

539. Xaa Val Xan Xab

540. Xim Val Xan Pro Pro Val Phe NH₂

541. Xin Val Xan Pro Pro Val Phe NH₂

542. Xio Val Xan Pro Pro Val Phe NH₂

543. Xip Val Xan Pro Pro Val Phe NH₂

544. Xiq Val Xan Pro Pro Val Phe NH₂

545. Xkd Val Xan Pro Pro Val Phe NH₂

546. Xim Val Xan Pro Pro Val NH₂

547. Xin Val Xan Pro Pro Val NH₂

548. Xio Val Xan Pro Pro Val NH₂

549. Xip Val Xan Pro Pro Val NH₂

550. Xiq Val Xan Pro Pro Val NH₂

551. Xkd Val Xan Pro Pro Val NH₂

552. Xim Val Xan Pro Pro NH₂

553. Xin Val Xan Pro Pro NH₂

554. Xio Val Xan Pro Pro NH₂

555. Xip Val Xan Pro Pro NH₂

556. Xiq Val Xan Pro Pro NH₂

557. Xkd Val Xan Pro Pro NH₂

558. Xaa Val Xan Pro Pro Val Xir

559. Xaa Val Xan Pro Pro Val Xis

560. Xaa Val Xan Pro Pro Val Xit

561. Xaa Val Xan Pro Pro Val Xiu

562. Xaa Val Xan Pro Pro Xiv

563. Xaa Val Xan Pro Pro Xiw

564. Xaa Val Xan Pro Pro Xiy

565. Xaa Val Xan Pro Pro Xix

566. Xaa Val Xan Pro Xiz

567. Xaa Val Xan Pro Xka

568. Xaa Val Xan Pro Xkb

569. Xaa Val Xan Pro Xkc

570. Xke Val Xan Pro Pro Val Phe NH₂

571. Xkf Val Xan Pro Pro Val Phe NH₂

572. Xkg Val Xan Pro Pro Val Phe NH₂

573. Xkh Val Xan Pro Pro Val Phe NH₂

574. Xke Val Xan Pro Pro Val NH₂

575. Xkf Val Xan Pro Pro Val NH₂

576. Xkg Val Xan Pro Pro Val NH₂

577. Xkh Val Xan Pro Pro Val NH₂

578. Xke Val Xan Pro Pro NH₂

579. Xkf Val Xan Pro Pro NH₂

580. Xkg Val Xan Pro Pro NH₂

581. Xkh Val Xan Pro Pro NH₂

582. Xaa Xcz Pro Pro Val Phe NH₂

583. Xed Val Xhf Pro Xhr NH₂

584. Val Val Xan Pro Pro Val Phe

585. Xaa Val Xan Pro Pro Val

586. Xaa Val Xki Pro Pro Val Phe NH₂

587. Xaa Val Xan Pro Pro Val Xhz NH₂

588. Xaa Val Xan Pro Pro Val Xah NH₂

589. Xaa Val Xan Pro Pro Val Tyr NH₂

590. Xaa Val Xan Pro Pro Phe Phe NH₂

591. Xaa Val Xan Pro Pro Val Xkj NH₂

592. Xaa Val Xan Xbb

593. Xaa Val Xan Pro Pro Xab

594. Xaa Val Xan Xfp

595. Xaa Val Xan Xbg

596. Xaa Val Xan Xbx

597. Xaa Val Xan Pro Xbg

598. Xaa Val Xan Pro Pro Ile NH₂

599. Xaa Val Xan Pro Pro Leu NH₂

600. Xaa Val Xan Pro Pro Xlv NH₂

601. Xaa Val Xan Xfo

602. Xaa Val Xan Pro Pro Xlw Phe NH₂

603. Xaa Val Xan Pro Pro Xlx Phe NH₂

604. Xaa Val Xan Pro Pro Val Xlw NH₂

605. Xaa Val Xan Pro Xkr

606. Xar Val Xan Pro Xfy

607. Xat Xai Xan Pro Xfy

608. Xaa Val Xan Pro Pro Val Xlv NH₂

609. Xaa Val Xan Pro Xkc

610. Xaa Val Xan Pro Xbm

611. Xaa Val Xan Pro Xka

612. Xaa Val Xan Pro Xks

613. Xaa Val Xan Pro Xiz

614. Xaa Val Xan Pro Xbk

615. Xaa Val Xan Pro Xen

616. Xaa Val Xan Pro Xhi

617. Xaa Val Xan Pro Xbh

618. Xaa Val Xan Pro Xfd

619. Xaa Val Xan Pro Xgn

620. Xbo Val Xan Pro Xfy

621. Xat Val Xan Pro Xfy

622. Xas Val Xan Pro Xfy

623. Xaa Val Xam Pro Xfy

624. Xcl Val Xan Pro Xfy

625. Xci Val Xan Pro Xfy

626. Xaa Val Xhz Pro Xfy

627. Xaa Val Xan Pro Xkt

628. Xaa Val Xan Pro Xku

629. Xaa Val Xan Pro Xkv

630. Xaa Val Xan Pro Xkw

631. Xaa Val Xhh Pro Xfy

632. Xaa Ile Xan Pro Xfy

633. Xaa Val Xan Xak Xfy

634. Xaa Val Xan Pro Xkb

635. Xat Val Xan Pro Xbg

636. Xar Val Xan Pro Xbg

637. Xar Val Xam Pro Xfy

638. Xaa Val Xan Pro Pro Xga

639. Xaa Val Xan Pro Xkx

640. Xaa Val Xan Pro Pro Leu Phe NH₂

641. Xaa Val Xan Pro Pro Ile Phe NH₂

642. Xaa Val Xan Pro Xky

643. Xaa Val Xan Pro Xkz

644. Xaa Val Xan Pro Xfr

645. Xaa Val Xam Pro Pro NH₂

646. Xaa Val Xan Pro Xla

647. Xaa Val Xan Pro Xlb

648. Xaa Val Xan Pro Xlc

649. Xaa Val Xan Pro Xld

650. Xaa Val Xan Pro Xkk

651. Xaa Val Xan Pro Xek

652. Xaa Val Xan Pro Xle

653. Xaa Val Xan Pro Xlf

654. Xaa Val Xan Pro Xlg

655. Xaa Val Xan Pro Xkl

656. Xaa Val Xan Pro Xlh

657. Xkm Val Xan Pro Xfy

658. Xaa Val Xan Pro Xli

659. Xaa Val Xan Pro Xlk

660. Xkn Val Xan Pro Xfy

661. Xaa Val Xan Pro Xll

662. Xaa Val Xan Pro Xlm

663. Xaa Val Xan Pro Xfk

664. Xaa Xma Xan Pro Xfy

665. Xaa Val Xhg Pro Xfy

666. Xaa Val Xhy Pro Xfy

667. Xaa Val Xan Pro Xln

668. Xaa Xai Xan Pro Xfy

669. Xaa Val Xao Pro Xfy

670. Xaa Val Xan Pro Xlo

671. Xaa Val Xan Pro Xko

672. Xaa Val Xan Pro Xkp

673. Xaa Val Xan Pro Xlp

674. Xaa Val Xan Pro Xlq

675. Xaa Val Xan Pro Pro Xlr

676. Xaa Val Xhf Pro Xfy

677. Xaa Val Xan Pro Xls

678. Xaa Val Xan Pro Xlt

679. Xby Val Xan Pro Xfy

680. Xkq Val Xan Pro Xfy

681. Xaa Val Xan Pro Xlu

Examples for the MS-characterization of the synthesized novel compounds are given in the following table.

    ______________________________________                                         EXAMPLE    Fast atom bombardment MS analysis.                                   No.!       Mol.-Weight (measured)!                                            ______________________________________                                         3.         798                                                                 16.        810                                                                 19.        812                                                                 20.        812                                                                 23.        812                                                                 25.        812                                                                 26.        812                                                                 28.        811                                                                 30.        825                                                                 33.        881                                                                 34.        845                                                                 37.        649                                                                 38.        737                                                                 50.        550                                                                 51.        551                                                                 52.        731                                                                 56.        550                                                                 65.        566                                                                 66.        566                                                                 87.        635                                                                 93.        704                                                                 101.       853                                                                 204.       740                                                                 214.       619                                                                 215.       845                                                                 227.       649                                                                 230.       691                                                                 233.       717                                                                 234.       641                                                                 239.       579                                                                 246.       595                                                                 347.       566                                                                 349.       566                                                                 351.       669                                                                 352.       656                                                                 357.       669                                                                 403.       811                                                                 404.       812                                                                 405.       812                                                                 597.       635                                                                 598.       665                                                                 699.       665                                                                 600.       749                                                                 601.       594                                                                 602.       852                                                                 603.       826                                                                 604.       804                                                                 605.       677                                                                 606.       655                                                                 607.       670                                                                 608.       848                                                                 609.       608                                                                 610.       627                                                                 611.       565                                                                 612.       633                                                                 613.       642                                                                 614.       642                                                                 615.       731                                                                 616.       657                                                                 617.       647                                                                 618.       648                                                                 619.       663                                                                 620.       669                                                                 621.       655                                                                 622.       655                                                                 623.       655                                                                 624.       681                                                                 625.       667                                                                 626.       689                                                                 627.       565                                                                 628.       579                                                                 629.       593                                                                 630.       594                                                                 631.       659                                                                 632.       655                                                                 633.       655                                                                 634.       580                                                                 635.       648                                                                 636.       648                                                                 637.       669                                                                 638.       788                                                                 639.       647                                                                 640.       812                                                                 641.       812                                                                 642.       668                                                                 643.       709                                                                 644.       717                                                                 645.       566                                                                 646.       684                                                                 647.       657                                                                 648.       684                                                                 649.       634                                                                 650.       630                                                                 651.       619                                                                 652.       699                                                                 653.       608                                                                 654.       655                                                                 655.       680                                                                 656.       590                                                                 657.       670                                                                 658.       655                                                                 659.       669                                                                 660.       627                                                                 661.       607                                                                 662.       621                                                                 663.       649                                                                 664.       627                                                                 665.       669                                                                 666.       695                                                                 667.       628                                                                 668.       655                                                                 669.       655                                                                 670.       607                                                                 671.       646                                                                 672.       660                                                                 673.       685                                                                 674.       628                                                                 675.       754                                                                 676.       656                                                                 677.       635                                                                 678.       621                                                                 679.       669                                                                 680.       656                                                                 681.       667                                                                 ______________________________________                                    

                  TABLE I                                                          ______________________________________                                         Sequence Identification of Compounds Prepared                                  According to Examples 1 and 2                                                  Compound Number(s)    Sequence ID Number                                       ______________________________________                                         3, 9, 26-28, 30-33, 35, 36,                                                                          1                                                        95-117, 341-343, 416, 417,                                                     424-426, 526, 540-545, 570-573, 586                                            38, 39, 52, 86-91, 93, 214-246,                                                                      2                                                        350-362, 366-368, 395-398,                                                     433-452, 459, 460, 469-478,                                                    504, 506, 508, 510, 530,                                                       566-569, 583, 597, 606, 607, 609-611,                                          613-626, 631, 633-637, 644, 650,                                               651, 654, 655, 657, 660, 663, 665,                                             666, 669, 671, 672, 676, 679, 680                                              605, 612, 627, 628-630, 639, 642, 643,                                         645-649, 652, 653, 656, 658, 659, 661,                                         662, 667, 670, 673, 674, 677, 678, 681                                         4-7, 10, 11, 160-188, 406, 558-561, 587,                                                             3                                                        588, 591, 604, 608                                                             8                     4                                                        12                    5                                                        13, 392, 403, 602, 603                                                                               6                                                        14, 641               7                                                        15, 16, 29            8                                                        17, 18                9                                                        19, 20                10                                                       21, 22, 247-264, 303-313, 582                                                                        11                                                       23, 402               12                                                       24, 400               13                                                       25, 401               14                                                       34, 590               15                                                       37, 118-138, 344-346, 585                                                                            16                                                       40, 45, 189-213, 369-372, 383-388,                                                                   17                                                       503, 505, 507, 509, 531, 538, 563-565,                                         593, 600, 638, 675                                                             41-43, 48, 49, 527    18                                                       44                    19                                                       46, 50, 51, 62-65, 70, 139-159, 347-349                                                              20                                                       414, 415, 420, 421, 430-432, 528,                                              552-557, 578-581                                                               47                    21                                                       53-61, 78, 422, 423, 539, 592, 594-596                                                               22                                                       601                                                                            66, 67, 94, 410, 524  23                                                       68, 69, 284-302, 325-335                                                                             24                                                       73, 83-85             25                                                       92, 664, 668          26                                                       265-283, 314-324      27                                                       336                   28                                                       337, 338              29                                                       339, 340, 377-382, 399                                                                               30                                                       363-365               31                                                       373, 374              32                                                       375, 376              33                                                       389-391               34                                                       393, 394              35                                                       404, 640              36                                                       405                   37                                                       407                   38                                                       408                   39                                                       409                   40                                                       411, 412, 418, 419, 427-429,                                                                         41                                                       546-551, 574-577                                                               413, 413(a), 453, 454, 457,                                                                          42                                                       458, 512 514, 516, 518                                                         455, 456, 632         43                                                       465-468               44                                                       461-464               45                                                       479-502               46                                                       515, 517              47                                                       513                   48                                                       519                   49                                                       520                   50                                                       521                   51                                                       522                   52                                                       523                   53                                                       525                   54                                                       529                   55                                                       584                   56                                                       589                   57                                                       598                   58                                                       599                   59                                                       ______________________________________                                    

The symbols Xaa . . . in the summary have the following meanings: ##STR5##

The ending --NH₂ has the meaning that the C-terminal amino acid is in its amide form.

Compounds of this invention may be assayed for anti-cancer activity by conventional methods, including for example, the methods described below.

A. In vitro methodology

Cytotoxicity was measured using a standard methodology for adherent cell lines such as the microculture tetrazolium assay (MTT). Details of this assay have been published (Alley, MC et al, Cancer Research 48:589-601, 1988). Exponentially growing cultures of tumor cells such as the HT-29 colon carcinoma or LX-1 lung tumor are used to make microtiter plate cultures. Cells are seeded at 5000-20,000 cells per well in 96-well plates (in 150 μl of media), and grown overnight at 370° C. Test compounds are added, in 10-fold dilutions varying from 10⁻⁴ M to 10⁻¹⁰ M. Cells are then incubated for 48 hours. To determine the number of viable cells in each well, the MTT dye is added (50 μl of 3 mg/ml solution of 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide in saline). This mixture is incubated at 370° C. for 5 hours, and then 50 μl of 25% SDS, pH2 is added to each well. After an overnight incubation, the absorbance of each well at 550 nm is read using an ELISA reader. The values for the mean ±SD of data from replicated wells are calculated, using the formula % T/C (% viable cells treated/control). ##EQU1## The concentration of test compound which gives a T/C of 50% growth inhibition was designated as the IC₅₀ value. The following results were obtained:

    ______________________________________                                         COMPOUND OF EXAMPLE                                                                               IC.sub.50  M!                                               ______________________________________                                         14                 3 × 10.sup.-7                                         19                 8 × 10.sup.-5                                         20                 2 × 10.sup.-9                                         21                 >10.sup.-4                                                  23                 2 × 10.sup.-5                                         25                 2 × 10.sup.-4                                         26                 6 × 10.sup.-8                                         27                 5 × 10.sup.-6                                         29                 >10.sup.-4                                                  30                 >10.sup.-4                                                  52                 5 × 10.sup.-5                                         55                 2 × 10.sup.-6                                         56                 4 × 10.sup.-7                                         57                 4 × 10.sup.-6                                         58                   10.sup.-5                                                 62                 3 × 10.sup.-5                                         65                 4 × 10.sup.-7                                         66                 2 × 10.sup.-7                                         68                 6 × 10.sup.-7                                         73                 2 × 10.sup.-5                                         86                   10.sup.-7                                                 87                 4 × 10.sup.-8                                         88                 2 × 10.sup.-9                                         93                 5 × 10.sup.-9                                         94                 >10.sup.-4                                                  95                 5 × 10.sup.-7                                         102                  10.sup.-4                                                 146                2 × 10.sup.-5                                         157                2 × 10.sup.-4                                         204                4 × 10.sup.-9                                         214                  10.sup.-9                                                 215                3 × 10.sup.-9                                         227                  10.sup.-8                                                 230                  10.sup.-9                                                 233                  10.sup.-9                                                 234                .sup. 3 × 10.sup.-10                                  238                6 × 10.sup.-7                                         239                6 × 10.sup.-8                                         241                >10.sup.-6                                                  246                  10.sup.-8                                                 247                >10.sup.-4                                                  284                6 × 10.sup.-7                                         339                >10.sup.-6                                                  340                >10.sup.-6                                                  347                3 × 10.sup.-7                                         349                6 × 10.sup.-7                                         351                7 × 10.sup.-8                                         352                2 × 10.sup.-8                                         357                8 × 10.sup.-9                                         361                >10.sup.-6                                                  400                2 × 10.sup.-4                                         404                4 × 10.sup.-7                                         405                3 × 10.sup.-7                                         411                >10.sup.-5                                                  417                2 × 10.sup.-5                                         521                >10.sup.-4                                                  ______________________________________                                    

Further compounds of this invention were assayed for anti-cancer activity by the crystal violet assay for cytotoxicity.

This assay was performed according to the method described by Flick H. and Gifford, G. E., J. Immunol. Meth. 68, 167-175 (1984). Proteins of surviving adherent cells are stained after exposure to a cytotoxic drug and quantitated calorimetrically. Test cells (CX-I; colon carcinoma, human) were plated in 96 flat bottom microtiter plates at a density of 2-3×10³ cells/well and incubated under standard culture conditions (RPMI 1640 with 10% fetal calf serum and 1% non-essential amino acids) at 37° C. and 5% CO₂ for one day. The cells were then exposed to several concentrations of the test compound. Controls were incubated in medium alone. After a further incubation period of 72 h, the culture medium was removed by flicking and 50 μl of a crystal violet staining solution were added to each well. After a staining period of 20 min, the staining solution was removed and the plates were washed vigorously with water until all unbound dye was removed. The remaining insoluble dye crystals were dissolved by adding 100 μl of a solution containing 50% ethanol and 0.1% acetic acid to each well. The absorbance of each well was determined using an ELISA microtiter plate reader at 540 nm (Titertec Multiscan, Flow Lab., Meckenheim).

The concentration of test compound which gives a T/C of 50% growth inhibition was designated as the IC₅₀. The following results were obtained:

    ______________________________________                                         COMPOUND OF EXAMPLE                                                                               IC.sub.50  M!                                               ______________________________________                                         1                  9 × 10.sup.-8                                         2                  4 × 10.sup.-8                                         3                  6 × 10.sup.-7                                         8                  5 × 10.sup.-6                                         9                  4 × 10.sup.-8                                         10                 6 × 10.sup.-8                                         13                 2 × 10.sup.-7                                         16                 9 × 10.sup.-7                                         28                 3 × 10.sup.-8                                         31                 10.sup.-5                                                   33                 2 × 10.sup.-5                                         34                 4 × 10.sup.-8                                         36                 2 × 10.sup.-5                                         37                 4 × 10.sup.-7                                         38                 .sup. 3 × 10.sup.-10                                  48                 4 × 10.sup.-7                                         50                 2 × 10.sup.-7                                         51                 5 × 10.sup.-7                                         59                 8 × 10.sup.-6                                         101                2 × 10.sup.-4                                         406                4 × 10.sup.-7                                         407                9 × 10.sup.-7                                         408                2 × 10.sup.-6                                         538                10.sup.-10                                                  ______________________________________                                    

B. In vivo methodology

Compounds of this invention were further tested in pre-clinical assay for in vivo activity which is indicative of clinical utility. Such assays were conducted with nude mice into which tumor tissue, preferably of human origin, had been transplanted (xenografted), as is well known in this field. Test compounds were evaluated for their anti-tumor efficacy following administration to the xenograft-bearing mice.

More specifically, human breast tumors (MX-1) which had been grown in athymic nude mice were transplanted into new recipient mice, using tumor fragments which were about 50 mg in size. The day of transplantation was designated as day 0. Six to ten days later, mice were treated with the test compounds given as an intravenous injection, in groups of 5-10 mice at each dose. Compounds were given every other day, for 3 weeks, at doses from 1-100 mg/kg body weight. Tumor diameters and body weights were measured twice weekly. Tumor volumes were calculated using the diameters measured with Vernier calipers, and the formula

    (length×width.sup.2)/2=mm.sup.3 of tumor volume

Mean tumor volumes are calculated for each treatment group, and T/C values determined for each group relative to the untreated control tumors.

In the second example as shown in FIG. 2., mice were treated with compound example #234, at 25 mg/kg 3 times a week for 3 weeks. All tumors in the treated group disappeared, while the control tumors grew so large the mice were sacrificed. No regrowth of the tumor was observed in the treated mice.

Representative Compounds Tested in Vivo

Additional compounds were also tested in the MX-1 model as described above. Compounds were administered i.v. Compounds which had good activity in the MX-1 model were also tested in additional in vivo models.

    ______________________________________                                         EXAMPLE      ACTIVITY*   COMMENTS                                              ______________________________________                                         2            +           tumor growth delay                                    37           ++          regressions,                                                                   active in other models                                38           +++         cures, active in other                                                         models                                                50           +++         cures, active in other                                                         models                                                230          ++          regressions                                           595          +++         cures, active in other                                                         models                                                610          ++          regressions                                           611          ++          regressions                                           627          +++         cures, active in other                                                         models                                                629          +++         cures, active in other                                                         models                                                ______________________________________                                           *!:                                                                           + tumor growth delay                                                           ++ regressions                                                                 +++ cures                                                                      other models P388 leukemia, OVCAR ovarian carcinoma, LOX human melanoma  

These data show that the new compounds possess good tumor inhibiting properties.

    __________________________________________________________________________     SEQUENCE LISTING                                                               (1) GENERAL INFORMATION:                                                       (iii) NUMBER OF SEQUENCES: 59                                                  (2) INFORMATION FOR SEQ ID NO:1:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:                                        XaaValXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:2:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:                                        XaaValXaaProXaa                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:3:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:                                        XaaValXaaProProValXaa                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:4:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:                                        XaaValXaaProProValHis                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:5:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:                                        XaaXaaXaaProProValTrp                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:6:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:                                        XaaValXaaProProXaaPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:7:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:                                        XaaValXaaProProIlePhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:8:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:                                        XaaValXaaProXaaValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:9:                                               (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:                                        XaaValXaaXaaProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:10:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:                                       XaaValXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:11:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:                                       XaaXaaProProValPhe                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:12:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:                                       XaaIleXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:13:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:                                       XaaXaaXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:14:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:                                       XaaLeuXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:15:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:                                       XaaValXaaProProPhePhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:16:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:                                       XaaValXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:17:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:                                       XaaValXaaProProXaa                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:18:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:                                       XaaValXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:19:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:                                       XaaXaaXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:20:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:                                       XaaValXaaXaaProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:21:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:                                       XaaValXaaProXaaVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:22:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22:                                       XaaValXaaXaa                                                                   (2) INFORMATION FOR SEQ ID NO:23:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23:                                       XaaXaaXaaProPro                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:24:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24:                                       XaaXaaProPro                                                                   1                                                                              (2) INFORMATION FOR SEQ ID NO:25:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25:                                       XaaValXaaPro                                                                   1                                                                              (2) INFORMATION FOR SEQ ID NO:26:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26:                                       XaaXaaXaaProXaa                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:27:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:27:                                       XaaXaaProProVal                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:28:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:28:                                       XaaValProProValPhe                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:29:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29:                                       XaaValProPro                                                                   1                                                                              (2) INFORMATION FOR SEQ ID NO:30:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 4 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30:                                       XaaXaaProXaa                                                                   1                                                                              (2) INFORMATION FOR SEQ ID NO:31:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:31:                                       XaaValXaaProXaaPhe                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:32:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:32:                                       XaaXaaProProXaa                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:33:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:33:                                       XaaXaaProXaaPhe                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:34:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:34:                                       XaaValXaaProProPhePhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:35:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:35:                                       XaaValXaaProProXaaXaa                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:36:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:36:                                       XaaValXaaProProLeuPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:37:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:37:                                       XaaValXaaProProIlePhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:38:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:38:                                       XaaValXaaProProValAla                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:39:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:39:                                       XaaXaaXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:40:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:40:                                       XaaXaaXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:41:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:41:                                       XaaValXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:42:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:42:                                       XaaValXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:43:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:43:                                       XaaIleXaaProXaa                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:44:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:44:                                       XaaValXaaProXaaVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:45:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:45:                                       XaaValXaaProXaaLeuPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:46:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:46:                                       XaaValXaaProXaaXaa                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:47:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:47:                                       XaaLeuXaaProProXaa                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:48:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:48:                                       XaaLeuXaaProProXaa                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:49:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:49:                                       XaaLysXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:50:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:50:                                       XaaLysXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:51:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:51:                                       XaaLysXaaProPro                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:52:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 5 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:52:                                       XaaLysXaaProXaa                                                                15                                                                             (2) INFORMATION FOR SEQ ID NO:53:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:53:                                       XaaXaaXaaProProVal                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:54:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:54:                                       XaaXaaXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:55:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:55:                                       XaaValXaaProProValLys                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:56:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:56:                                       XaaValXaaProProValPhe                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:57:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 7 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:57:                                       XaaValXaaProProValTyr                                                          15                                                                             (2) INFORMATION FOR SEQ ID NO:58:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:58:                                       XaaValXaaProProIle                                                             15                                                                             (2) INFORMATION FOR SEQ ID NO:59:                                              (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 6 amino acids                                                      (B) TYPE: amino acid                                                           (C) STRANDEDNESS:                                                              (D) TOPOLOGY: linear                                                           (ii) MOLECULE TYPE: peptide                                                    (xi) SEQUENCE DESCRIPTION: SEQ ID NO:59:                                       XaaValXaaProProLeu                                                             15                                                                             __________________________________________________________________________ 

We claim:
 1. A peptide of the formula I

    R.sup.1 R.sup.2 N--CHX-CO-A-B-D-(E).sub.s -(F).sub.t -(G).sub.u -KI

where R¹ is alkoxy; alkyl; cycloalkyl; alkylsulfonyl; fluoroalkyl; aminosulfonyl, which may be substituted by alkyl; hydroxy; or benzyl, which may be substituted by up to three substituents independently selected from alkyl, alkoxy, nitro, halogen and CF₃ ; R² is hydrogen, alkyl; fluoroalkyl; or cycloalkyl; R¹ --N--R² together may form a 5-or 6-membered heterocycle which may be unsubstituted or substituted with one or more substituents independently selected from alkyl, N(CH₃)₂, nitro, CONH₂, and COOEt; A is a valyl, isoleucyl, leucyl, allo-isoleucyl, 2,2-dimethylglycyl, 3-tert-butylalanyl, 2-tert-butylglycyl, 3-cyclohexylalanyl, 2-ethylglycyl, 2-cyclohexylglycyl, norleucyl, 2-cyclopropylglycyl, 2-cyclopentylglycyl or norvalyl residue; B is an N-alkyl-valyl, -norvalyl, -leucyl, -isoleucyl, -2-tert-butylglycyl, -3-tert-butylalanyl, -2-ethylglycyl, -norleucyl, -2-cyclopropylglycyl, -2-cyclopentylglycyl, or -2-cyclohexylglycyl residue; D is a prolyl, homo-prolyl, hydroxyprolyl, 3,4-dehydroprolyl, 4-fluoroprolyl, 3-methylprolyl, 4-methylprolyl, 5-methylprolyl, azetidine-2-carbonyl, 3,3-dimethylprolyl, 4,4-difluoroprolyl, oxazolidine-4-carbonyl or thiazolidine-4-carbonyl residue; E is a prolyl, homoprolyl, hydroxyprolyl, 3,4-dehydroprolyl, 4-fluoroprolyl, 3-methylprolyl, 4-methylprolyl, 5-methylprolyl, azetidine-2-carbonyl, 3,3-dimethylprolyl, 4,4-difluoroprolyl, oxazolidine-4-carbonyl or thiazolidine-4-carbonyl residue; F and G are independently selected from the group consisting of prolyl, homoprolyl, hydroxyprolyl, thiazolidinyl-4-carbonyl, 1-aminopentyl-1- carbonyl, valyl, 2-tert-butylglycyl, isoleucyl, leucyl, 3-cyclohexylalanyl, phenylalanyl, N-methylphenylalanyl, tetrahydroisoquinolyl-2-carbonyl, 3-thiazolylalanyl, 3-thienylalanyl, histidyl, 1-aminoindyl-1-carbonyl, 3-pyridylalanyl, 2-cyclohexylglycyl norvalyl, norleucyl, tryptophanyl, neopentylglycyl, β-alanyl and 3-naphthylalanyl residues; X is hydrogen; alkyl; cycloalkyl; --CH₂ -cyclohexyl or arylalkyl; s, t, and u are independently 0 or 1; and K is hydroxy, alkoxy, benzyloxy, phenyloxy or an amino moiety of the formula R⁵ --N--R⁶, whereinR⁵ is selected from the group consisting of: hydrogen; hydroxy; alkoxy; substituted or unsubstituted benzyloxy; substituted or unsubstituted phenoxy; fluorine-substituted or unsubstituted, linear or branched alkyl; cycloalkyl; and substituted and unsubstituted benzyl; and R⁶ is selected from the group consisting of: hydrogen; fluorine-substituted or unsubstituted, linear or branched alkyl; aryl; cycloalkylalkyl; arylalkyl; heteroarylalkyl; heteroaryl; (CH₂ CH₂ O)_(y) R, wherein y is 1 to 5 and R is an alkyl group; --CHR⁷ -5-membered heteroaryl, wherein the heteroaryl group is substituted or unsubstituted and R⁷ is hydrogen, linear or branched C₁₋₄ -C₅ -alkyl, or benzyl, or R⁵ and R⁷ together form a group --(CH₂)₃ - or --(CH₂)₄ -; and NR^(a) R^(b), wherein R^(a) is hydrogen or methyl and R^(b) is a substituted or unsubstituted phenyl or benzyl group; or wherein R⁵, R⁶ and N together form a heteroaryl- or substituted heteroaryl-substituted 5- or 6-membered ring; or wherein R⁵, R⁶ and N together form a ring system selected from the group consisting of: ##STR6## or a salt thereof with a physiologically tolerated acid.
 2. A compound of formula I as defined in claim 1 wherein R¹ --N--R² together form a 5- or 6-membered heterocycle which may be unsubstituted or substituted with one or more substituents which may independently be selected from alkyl, N(CH₃)₂, nitro, oxo, CONH₂ and COOEt.
 3. The compound of claim 1 wherein K is an amino moiety of the formula R⁵ --N--R⁶ whereinR₅ is hydrogen; hydroxy; C₁₋₇ alkoxy; C₃₋₇ -cycloalkyl;benzyloxy, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; phenoxy; benzyloxy; halogen; C₁₋₄ -alkyl; cyano; hydroxy; N(CH)₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; phenyloxy, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; phenoxy; benzyloxy; halogen; C₁₋₄ -alkyl; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr; and COONH₂ ; C₁₋₇ -alkyl, optionally substituted by one or more fluorine atoms; or benzyl, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; phenoxy; benzyloxy; halogen; C₁₋₄ -alkyl; cyano; hydroxy; N(CH₃); COOMe; COOEt; COOiPr and COONH₂ ; R⁶ is hydrogen; norephedryl; norpseudoephedryl; quinolyl; pyrazyl; --CH₂ -benzimidazolyl; adamantyl; --CH₂ -adamantyl; alpha-methyl-benzyl; alpha-dimethylbenzyl;C₁₋₁₂ -alkyl, optionally substituted by one or more fluorine atoms; --(CH₂)_(v) -C₃₋₇ -cycloalkyl, wherein v=0,1,2, or 3; --(CH₂)_(v) -phenyl, wherein v=0,1,2, or 3, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; phenoxy; benzyloxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; --(CH₂)_(m) -naphthyl, wherein m=0 or 1, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxyl; N(CH₃)₂ ; COOMe; COOEt; COOiPr; or COONH₂ ; or --(CH₂)_(w) -benzhydryl, wherein w=0, 1, or 2, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; biphenyl, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; pyridyl, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; picolyl, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; --CH₂ --CH₂ -pyridyl, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; benzothiazolyl, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; benzopyrazolyl, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ - alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; benzoxazolyl, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; --(CH₂)_(m) -fluorenyl, wherein m is 0 or 1, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C,₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; pyrimidyl, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; --(CH₂)_(m) -indanyl, wherein m=0 or 1, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl, which may form a cyclic system; cyano; hydroxy; N(CH₃)₂ ; COOMe; COOEt; COOiPr and COONH₂ ; --(CH₂ CH₂ O)_(y) --CH₃, wherein y=0,1,2,3,4, or 5; --(CH₂ CH₂ O)_(y) --CH₂ CH₃, wherein y=0, 1,2,3,4, or 5; --NH-C₆ H₅, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; --NCH₃ -C₆ H₅, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; --NH--CH₂ C₆ H₅, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; --NCH₃ --CH₂ C₆ H₅, optionally having up to two substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; halogen; C₁₋₄ -alkyl which may form a cyclic system; cyano; hydroxy; COOMe; COOEt; COOiPr and COONH₂ ; 5-membered heteroaryl, optionally having up to three substituents independently selected from the group consisting of CF₃ ; nitro; C₁₋₇ alkylsulfonyl; C₁₋₄ alkoxy; thiomethyl; thioethyl; picolyl; acetyl; C₃₋₆ -cycloalkyl; thiophenyl; --CH₂ --COOEt; C₃ -4 -alkylene group forming a bicyclic system with the heterocycle; phenyl; phenyl substituted by up to three substituents which may independently be nitro, CF₃, CN, halogen, or C₁₋₄ -alkyl; benzyl; or benzyl substituted by up to three substituents which may independently be nitro, CF₃, halogen, C₁₋₄ -alkyl, C₁₋₇ -alkylsulfonyl, cyano, hydroxy or C₁₋₄ -dialkylamino; or --CHR⁷ -5-membered heteroaryl, wherein R⁷ is hydrogen; linear or branched C₁₋₅ alkyl or benzyl; or R⁷ and R⁵ together form a group --(CH₂)₃ - or --(CH₂)₄ -, optionally having up to two substituents which may independently be CF₃ ; nitro; cyano; halogen; COOMe; COOEt; COOiPr; CONH₂ ; C₁₋₄ -alkyl; C₁₋₄ -alkoxy; phenyl; benzyl; naphthyl or C₁₋₇ -alkylsulfonyl.
 4. A compound of formula I as defined in claim 1 wherein K is R⁵ --N--R⁶ which together may form structures selected from the group consisting of ##STR7## which may be unsubstituted or substituted with one or more substituents independently selected from the group consisting of CF₃, nitro, halogen, oxo, cyano, formyl, N,N-dimethylamino, C₁₋₆ -alkyl, C₃₋₆ -cycloalkyl, C₃₋₄ -alkylene group forming a bicyclic system with the heterocycle, C₁₋₄ -alkoxy, phenoxy, benzoxy, naphthyl, pyrimidyl, COOEt, pyrrolidinyl, piperidinyl, thienyl, pyrrolyl, CH₂ -CO-NCH(CH₃)₂, --CH₂ --CO-N(CH₂)₄, --CH₂ -CO-N(CH₂)₄ O, benzyl (which may be substituted by up to three substituents independently selected from the group consisting of nitro, halogen, CF₃, thiomethyl or the corresponding sulfoxide or sulfone, thioethyl or the corresponding sulfoxide or sulfone, C₁₋₄ -alkyl, and C₁₋₄ -alkoxy).
 5. A compound of formula I as defined in claim 1 wherein s, t and u are 1 and K is a hydroxy, alkoxy, phenoxy or benzyloxy moiety.
 6. A compound of formula I as defined in claim 1 wherein s and t are 1, u is 0 and K is a hydroxy, alkoxy, phenoxy or benzyloxy moiety.
 7. A compound of formula I as defined in claim 1 wherein s is 1, t and u are 0 and K is a hydroxy, alkoxy, phenoxy or benzyloxy moiety.
 8. A compound of formula I as defined in claim 1 wherein K is an amino moiety of the formula R⁵ --N--R⁶.
 9. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of a compound of formula I as defined in claim
 1. 10. A method of treating a tumor in a mammal comprising administering to a mammal bearing such a tumor, a tumor-inhibiting amount of a compound of formula I as defined in claim
 1. 